Even weirder, it looks like the corruption is being compressed suggesting it's being corrupted pre-encode. Have YouTube been reencoding all their content lately and something broke? Have the originals been corrupted?
In British railways, most trains have a thing called a Driver's Reminder Appliance (D.R.A). It's a button that the driver presses if the signal is red which prevents them from pulling off without checking the signal again - they have to disable it (and check the signal) before they can turn up the throttle and start moving again. At Clapham Junction, I have found a Driver Reminder Appliance Reminder. Which may be the most 'railway' thing I've ever seen.